Resonant bronze alloy



3,061,425 Patented Oct. 30, 1962 free 3,061,425 RESONANT BRONZE ALLOY Arthur N. Wells, P.0. Box 696, Belmont, Calif. No Drawing. Filed Jan. 12, 1960, Ser. No. 1,867 2 Claims. c1. 75-154 This invention relates generally to the processing of metals and pertains, more particularly, to a method of metal casting to produce castings having good resonating properties and which, at the same time, are relatively malleable.

It is the usual method in the manufacture of resonating metals to produce a metal by casting which has a rather dense granular structure and which is also characterized by substantial brittleness. These metals are characterized by the rather good segregation of their crystalline grains with such grains, however, being in contact. Because of this, a sound impulse Will travel from crystal to crystal with the relatively dense character of the metal permitting individual grain vibration to be accomplished. Other types of metal for resonating purposes utilize a principle of extreme hardness having a brittle character. In any event, metals of this type are always characterized by their brittleness which somewhat limits their use, preventing such metals from being subjected to a great deal of stress which might cause fracture or breakage thereof. Also, it is well known that metals of this type are d'iflicult to produce with any degree of uniformity in their sound response characteristics.

It is, therefore, of primary concern in connection with this invention to provide a resonating metal which produces its resonating characteristics and at the same time is relatively malleable.

A further object of this invention is to provide a metal of the character described which is to obtain by relatively simple and economical casting techniques and methods without requiring involved or complex processes or method steps which would render the production of the metal difiicult or expensive.

A further object of this invention is to provide a method of making a resonant metal which is characterized by its ability to be duplicated uniformly with a uniform response to sound vibrations, particularly high pitched and ultrasonic sounds.

Another object of this invention is to produce a sound resonant metal from alloys of any desired degree ,of malleability and to produce shapes in such alloys used to resonate with unusual sounds. For example, a tubular section of this resonant metal, interposed in a fluid transmission pipe line may so resonate with the pipe line noises as to preclude the objectionable effects of excessive emulsifications of the liquid.

Another object of this invention is to provide a sound resonant metal capable of propagating many unusual sounds, which metal may be in the form of a bar or wire to propagate many tonal sounds with a high degree of fidelity.

Another object of this invention is to provide a sound resonant metal which, in the form of a cylindrical tube, may greatly enhance, by its resonant effects, the functions of chimes, whistles and organ tubes and wherein also tubular sections of such metal may be interposed in a pipe which carries a liquid so as to resonate with the pipe line noises to thus preclude the objectionable effects of excessive emulsifications of the liquid.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

According to the present invention, it has been found that bronze alloys having more than 35% copper may be caused to exhibit extremely reliable qualities of both resonant and sound reflecting ability. Perhaps more important, it has also been discovered that such alloys may be produced with the abovementioned sound resonating and conducting characteristics without sacrificing any of the toughness or malleability which the basic alloy itself possesses.

It has been found that the addition of critical amounts of silica to bronze alloys as above specified will not alter their basic physical properties particularly malleability and toughness, but will exhibit the abovementioned' sound resonating and conducting characteristics. It has also been found that not only is the amount of silica added of critical importance but also the fineness of the material added is important.

The silica added apparently increases the surface tension of the molten metal and at the same time causes an interference in the normal formation of semi-crystalline rrgisses prior to congealing which produces the resonating e ect.

Insofar as the amount of silica utilized is concerned, it has been found that it must be within the range of from 0.1% to 2% by weight of the metal to which it is added. The particle size of the silica should approximate the size of the natural silica crystals in the mass of silica rock from which the ground silica is obtained. For example, a normal grind which has been used experimentally is approximately 250 mesh.

The exact quantity of silica to be added is determined by a study of the inter-crystalline voids in the congealed metal which it is desirable to fill. For example, in adding the silica to a chosen alloy, microscopic study of the alloy is indicated. If the voids appear materially less than filled, more silica must be added. The exact mesh size for the silica particles is also easily determined by microscopic study inasmuch as, as set forth above, the particle size of the silica should approximate the size of the natural silica crystals inthe silica rock from which the ground silica is obtained.

As the individual silica crystals melt when added to the molten bronze, the molten silica liquid still retains, to a degree, the molecular orientations of the silica crystals. This silica liquid then assumes an extremely high surface tension and the electrical effects thereof are induced in the body of the molten alloy which assumes also an increased surface tension. In order that the entire mass of the alloy be permeated with the molten silica, the quantity of silica must be within the range above specified in order to fill or substantially fill the inter-crystalline voids in the congealed alloy as above set forth.

Additionally, the silica must be added just prior to pouring the molten metal into the mold. Hence, a normal procedure would be as follows:

A quantity of bronze at about 2600" F. is poured from the furnace into a ladle and the alloy is then purged of gases and slag particles by the addition thereto of standard fluxing compounds and is then skimmed. The previously determined quantity of hard ground silica is added and stirred thoroughly for about 50 seconds. Thereafter, the surface is again skimmed and the metal poured into a mold.

As the metal cools, it does not pass through the usual phases of amorphous semi-solids. Instead, because of the interference of the silica, as well as the high surface tension eifect caused by the silica, the copper alone will form tiny crystalline nuclei which, upon further cooling will enlarge until finally the structure is that of segregated granules loosely tied with alloy bonds and with congealed silica in the interstices.

It has been found that the structure of the cast alloys is essentially cubic. The granules of nucleated hard crystals may vibrate freely as the alloy bonds therebetween are relatively loose and the silica has a high molecular volume. At the same time, the metal is not brittle because all of the granules are actually tied together by the alloy bonds. In fact, metals processed in accordance with the above manner are definitely inclined to be malleable.

Metal produced in accordance with this invention may be utilized in many different ways. For example, the metal can be used for the propagation of many tonal sounds with a high degree of fidelity. Bars or wires of such metal can be used for this purpose and the bar or wire can also be used for the purpose of conducting sound in a tortuous path, as for example around the corner.

Cylindrical tubes of the metal can be utilized in many different ways, for example in the formation of chimes, whistles and organ tubes. The resonant effects of the metal will greatly enhance the sound propagation characteristics in conjunction with such assemblies. Tubular sections of the resonant metal are also of beneficial use in conjunction with fluid transmission pipes. For example, the resonant characteristic of the metal will enable a tubular section, which is interposed in such a pipe, to resonate with the natural pipe line noises, usually sibilant or barely audible, which are produced by the movement of the fluid itself, and this resonating characteristic of the metal will tend to concentrate the reverberations in the region of the tubular section, to preclude excessive emulsification of the fluids being transmitted in the pipe.

I claim:

1. A bronze alloy and silica composition consisting of at least 35% copper and characterized by its malleability and sound resonating and conducting properties when cast, and wherein the silica is hard ground and in the proportion of from 0.1% to 2% by weight of the alloy and the particle size of the silica is approximately the same size as the natural silica crystals in the rock from which the silica is obtained.

2. A resonant metal characterized by its sound propagating and conducting properties of substantially tubular form, suitable for joining in pipe lines carrying fluids, to resonate with and to alter the sounds associated with emulsification, said resonant metal consisting of an alloy having at least 35% copper to which has been added from between 0.1% to 2% by weight of ground silica.

References Cited in the file of this patent UNITED STATES PATENTS 2,793,949 Imich May 28, 1957 2,894,838 Gregory July 14, 1959 2,938,790 Stedman et al. May 31, 1960 

1. A BRONZE ALLOY AND SILICA COMPOSITION CONSISTING OF AT LEAST 35% COPPER AND CHARACTERIZED BY ITS MALLEABILITY AND SOUND RESONATING AND CONDUCTING PROPERTIES WHEN CAST, AND WHEREIN THE SILICA IS HARD GROUND AND IN THE PROPORTION OF FROM 0.1% TO 2% BY WEIGHT OF THE ALLOY AND THE PARTICLE SIZE OF THE SILICA IS APPROXIMATELY THE WHICH THE SILICA IS OBTAINED. 